Talking organic gardening, compost (and rats!) with Christy Wilhelmi

Lisa Boone

In my Spreecast with organic gardener Christy Wilhelmi, author of the new book "Gardening for Geeks," I learned a lot: that white mildew can be treated with lactic acid, that you should never buy tall vegetable seedlings at the nursery and that volunteer tomatoes -- the ones that sprout up unplanned, perhaps from last year's fallen fruit -- are better than anything you plant intentionally.

In other words, she shared a few things not detailed in "Gardening for Geeks," which carries the breath-defying subtitle, "DIY Tests, Gadgets and Techniques That Utilize Microbiology, Mathematics and Ecology to Exponentially Maximize the Yield of Your Garden." The book teaches just about everything you need to know to grow your own organic food, but thanks in large part to the Spreecast audience who chimed in, we got some interesting new advice. You can listen to our chat or read this recap of highlights from our conversation:

Her motivation for writing a gardening book:

I took the opportunity to put everything that I teach in my classes into this book. There are a lot of gardening books that don’t tell you what's in that bag of soil you buy from the nursery or the details about the science behind composting and why it's important. I wanted to include the environmental impact of gardening.

Surprising thoughts on rats in your compost:

Critters are part of the garden. We can control it to a degree with bird netting or deer fencing. I've got three compost bins and they have slots for drainage, and the rats get in there. My thought is that they are helping the process. They are breaking down the organic matter that’s in there and they’re tilling it for me. And they go away in the daylight.

Strategies for controlling unwanted bugs:

Your two fingers are your best pest control. The best way to keep pests out of your garden is go out there and look at it. To some degree, having a garden without pests is like having children and expecting them to be well behaved all the time. It’s not reasonable.

What should we be planting right now (in Los Angeles and Southern California):

Warm weather crops: beans, corn, squash, eggplant, tomatoes and peppers as well as another round of lettuces and collard greens.

Volunteer tomatoes:

Volunteer tomatoes are what I call nature’s slap in the face. They do better than anything you plant on purpose. I like to let them go if they are not taking over a space where I already have something planned.

Favorite varieties of heirloom and open-pollinated [seeds produce plants that are identical to parent plant] tomatoes:

I am growing 14 varieties this year including Stupice, Yellow Pear, Black Cherry, Juane Flamme, Old German and Roma.

How to fight white mildew:

A lot of people will simply cut off the affected leaves. There is a formula of 50% water and 50% milk that some studies have shown prevents the spread of it. The lactic acid eats the fungus. My main thing is I cut off the leaves halfway through the summer. It [the mildew] is in the air and not something we can get rid of. I try to amend the soil so the plants can get through it. That hampers their growing ability. Keep the plant thriving by giving it a lot of nutrients at the soil and root level.

Healthy compost:

Your compost has to be in really good shape for it to benefit your plants. If you can, over the winter grow a cover crop -- peas, hairy vetch, fava beans and oats -- that are high in nitrogen. Cut it down, chop it up and put it in your compost bin. It adds nutrients that will go in to your garden. You’re not just decomposing waste but feeding your garden.

Advice for apartment dwellers:

There are some veggies that will grow in partial sun: lettuces, kale and chard. I like to point people to square-foot gardening. The efficiency is great for small spaces. In a 2-by-1 [planter] on your porch, you can plant eight heads of lettuce and have salad greens for two people for two to three months.

Buying vegetable plants instead of seeds:

Buy stout plants that aren’t much taller than the root ball that they are in. If you can buy smaller plants to start with, that’s going to get them off to a better start. Short and stocky, no fruit or flowers, and buy local.

Favorite vegetarian cookbooks:

I really like Rose Elliot’s cookbooks. And Ann Gentry of Real Food Daily.